1. Field of the Invention
This invention relates to a block structure providing an outwardly-extended actuation surface for an electric switch, and, more particularly, to a such a device in a form attachable to a flush-mounted automotive horn switch assembly.
2. Background Information
Before the widespread installation of driver-side air bags, vehicular horns were generally operated by mechanisms which were effectively concentric with the rotational axis of the steering wheel. One type of such a concentric mechanism is a ring extending mostly or completely around the rotational axis of the steering wheel between the central portion thereof and the steering wheel rim, which is used to steer the vehicle. The depression of such a ring caused the actuation of the vehicle horn. Another type of such a concentric mechanism includes a plate or flexible surface which is depressed at or near the center of rotation of the steering wheel to actuate the horn. A significant advantage of such a concentric mechanism is that the position of the horn actuator does not depend on the rotational position of the steering wheel.
The installation of a driver-side airbag requires establishment of an air bag compartment in a central region of the steering wheel, occupying much of the space within the steering wheel. The outer surface of this compartment must be a door which opens to allow deployment of the air bag in the event of a collision. To provide room for this compartment and door, the horn actuation mechanism was generally provided in the form of a pair of switch-actuating buttons moved outward along a crossbar extending between the wheel rim and the central rotatable means with which the steering wheel is mounted. In many instances, these buttons were mounted so that, when the horn switch was not actuated, the outer surfaces of the buttons were flush with the surrounding surfaces, which may include a button-mounting bezel and a surface of the crossbar.
A particular problem with this type of horn actuation is that these buttons cannot be easily located when the steering wheel is turned from its normal position, by which the wheels of the vehicle are aligned to move the vehicle straight forward. A typical emergency driving situation requires swerving the vehicle to avoid another vehicle or a pedestrian while sounding the horn to warn the other driver or pedestrian. However, to swerve the vehicle, the driver must move both his hands and the steering wheel in such a way that the horn buttons on the crossbar cannot be readily located. This presents a problem during both the night and day, since the driver can rarely afford to look away from a developing emergency driving situation. What is needed is a structure establishing tactile feedback concerning the location of the horn actuation buttons regardless of the movement of the steering wheel.
Another type of horn actuating surface presented within vehicles uses a flexible cover, not having a visible button, over a portion of the steering wheel. When this cover is depressed in the correct place, the horn is sounded. This correct place is typically identified with an icon, such as a picture of a horn. However, this type of identification provides little if any assistance at night or during an emergency situation. Thus, what is needed is a structure establishing tactile feedback concerning the location of the portion of the flexible cover which must be depressed to actuate the vehicle horn.